CNC Sinker EDM Copper from VT machining delivers precision Copper parts produced to your exact drawing. Sinker (die-sink) EDM burns a shaped electrode into metal to form precise cavities and blind features, and we tune every parameter to the behaviour of Copper, which is excellent electrical and thermal conductivity.
CNC Sinker EDM Capability for Copper
- Blind cavities & ribs
- Fine surface (VDI grades)
- Tolerance to ±0.005 mm
- Hardened tool steel
Copper Material Data
| Density | 8.94 g/cm³ |
|---|---|
| Tensile strength | 220–350 MPa |
| Yield strength (0.2%) | 70–330 MPa |
| Hardness | 40–100 HV |
| Melting point | 1083 °C |
| Thermal conductivity | 391 W/m·K |
| Thermal expansion | 17.0 ×10⁻⁶/K |
| Electrical conductivity | 101% |
| Machinability (C36000 = 100%) | 20% |
| Grades we run | C10100 OFE, C10200 OF, C11000 ETP, C14500 tellurium copper |
Published typical values for C11000 ETP. Other grades in the family differ — the certificate supplied with your order carries the actual heat-lot figures.
It smears rather than cuts. Razor-sharp uncoated tooling and high rake; if the print allows it, C14500 tellurium copper machines four times better at ~90% IACS.
How CNC Sinker EDM Copper Works
Material is removed from the Copper workpiece by controlled electrical discharges across a dielectric gap, with no mechanical contact. Flushing, on/off pulse timing and electrode/wire feed are set to balance speed against surface finish.
We start from your supplied geometry and tolerance scheme. The setup is designed to minimise re-clamping, which protects positional accuracy across features. A first article is verified against the drawing before the balance of the batch is released.
Achievable Tolerances for CNC Sinker EDM Copper
| Feature | Standard | Precision |
|---|---|---|
| Profile dimension | ±0.010 mm | ±0.002 mm |
| Internal corner radius | 0.15 mm | 0.05 mm |
| Taper control over 50 mm | 0.02 mm | 0.005 mm |
| Surface finish (skim passes) | Ra 0.8 µm | Ra 0.2 µm |
| Recast layer | 10 µm | 2 µm (fine skim) |
| Start-hole diameter | 1.0 mm | 0.25 mm |
| Workpiece hardness | no limit (conductive) | no limit (conductive) |
Standard is what a normal quotation assumes. Precision is available on nominated features and is priced separately, because it needs extra setups, in-process gauging and CMM verification. Call out only the features that need it — blanket-tightening a drawing is the single most common reason a quote comes back expensive.
CNC Sinker EDM Tolerances & Surface Finish
EDM holds tolerances to roughly ±0.002–0.005 mm with no cutting force on the Copper part, producing fine, controlled surface textures and sharp internal corners impossible to mill.
The tightest tolerances are reserved for the features your drawing flags as critical. Share your tolerance scheme and we will confirm what is realistic before quoting.
Secondary Operations & Finishing
Most Copper parts need some finishing, which we manage in-house or through vetted partners. Options include deburring and edge-breaking, heat treatment, surface grinding, polishing, and plating or anodising for corrosion resistance and appearance. Give us the finished-part requirement and we will sequence every operation correctly.
Design Tips for CNC Sinker EDM Copper
Small design adjustments often cut cost and lead time. EDM suits sharp internal corners, thin ribs and hardened Copper that cannot be milled; allowing a small corner radius where possible speeds the cut. If you send your model early, we will return practical DFM feedback before you commit to production.
Working with Copper
Copper is excellent electrical and thermal conductivity. We translate those properties into a process plan: the right tooling, speeds, feeds and fixturing for the alloy.
Where the grade, temper or heat-treat condition matters to performance, we confirm it with you and can supply material certificates. Material is procured to recognised standards for consistent, repeatable results.
CNC Sinker EDM Quality & Inspection
Quality is built in, not inspected on. We monitor key features during the run and confirm them at final inspection, with CMM verification available for tight tolerances. We provide the inspection and traceability records your quality system requires.
Applications of CNC Sinker EDM Copper
Copper parts made this way are found throughout aerospace, medical, automotive, electronics and industrial equipment. Prototype, bridge and production volumes are all welcome.
How to Order CNC Sinker EDM Copper
Starting your project takes one email. Send your CAD or 2D drawing, the Copper grade and condition, the quantity and any finish or inspection requirements. We respond quickly with price, lead time and any DFM notes, in clear English.
Parts We Have Run in Copper
Three representative CNC Sinker EDM Copper jobs, with the callouts that actually drove the process plan. Yours will differ — these are here so you can judge whether your part is in our range before you spend time on an RFQ.
Injection mould cavity rib
- Material
- Copper
- Size
- 0.25 mm wide × 8 mm deep
- Key callouts
- Width ±0.005 mm, VDI 21 finish
- Batch
- 45 pcs
Sinker EDM with a graphite electrode; a cutter that thin would break in the first pass.
Spline broach section
- Material
- Copper
- Size
- Ø28 × 40 mm
- Key callouts
- Involute profile ±0.005 mm, Ra 0.4 µm
- Batch
- 60 pcs
Wire EDM after hardening to 62 HRC — the profile would not survive being cut soft and heat-treated.
Extrusion die
- Material
- Copper
- Size
- 120 × 120 × 25 mm
- Key callouts
- Profile ±0.005 mm, internal corner R0.1 mm
- Batch
- 35 pcs
Cut in four skim passes; the first pass is speed, the last three are finish and accuracy.
Finishing Options for Copper
| Finish | Thickness / effect | Why it gets specified |
|---|---|---|
| Tin plate | 3–15 µm | Solderable, prevents oxidation |
| Silver plate | 2–10 µm | Lowest contact resistance for RF and power |
| Nickel underplate | 2–5 µm | Diffusion barrier under tin or gold |
| Gold flash | 0.05–1 µm | Contact surfaces, over nickel |
| Deburr / edge break | 0.05–0.3 mm | All parts unless the drawing says otherwise |
| Bead blast | Ra 1.6–3.2 µm | Uniform matt finish, hides tool marks |
| Laser marking | — | Part number, lot code, data matrix |
No drawing yet? Build one in the browser.
Set the metal, dimensions and features, watch the 3D model update as you type, then switch to the 2D sheet to add dimensions and tolerances. Download it or send it straight to us with your RFQ.
What We Need to Quote CNC Sinker EDM Copper
- GeometrySTEP or IGES for the 3D model, plus a PDF drawing if you have tolerance callouts. A dimensioned sketch is enough to start.
- MaterialThe exact Copper grade and condition — temper, heat-treat state or hardness. If you are not sure, tell us the function and we will suggest one.
- QuantityPrototype count and the expected annual volume. Both change how the part is made and therefore what it costs.
- TolerancesWhich features are critical. Everything else runs to our standard tolerance, which is what keeps the price sensible.
- FinishSurface treatment, cosmetic requirements, and any faces that must be masked.
- DocumentsWhether you need a material certificate, dimensional report, FAIR or PPAP with the shipment.
Missing something from the list is not a problem — send what you have. We will come back with the specific questions rather than a generic form.
Other Metals for CNC Sinker EDM
Other Processes for Copper
Send the drawing, the Copper grade and the quantity. You get pricing, lead time and any DFM notes back — usually within one business day.
Request a QuoteFrequently Asked Questions
How clean are the edges produced by CNC Sinker EDM on Copper?
Machined Copper edges are clean and to specification; edge-break or deburring is added when your drawing calls for it.
Does CNC Sinker EDM Copper require dedicated tooling?
Wire EDM needs no shaped tooling; sinker EDM uses a shaped electrode we produce in-house for your cavity.
Can VT machining make custom Copper parts to my drawing?
Yes. Copper Copper EDM machining is made to order from your CAD/2D drawing. Share your geometry, material grade, tolerance and quantity and we will confirm feasibility, lead time and pricing.
What tolerances can you hold for CNC Sinker EDM Copper?
Achievable tolerances for Copper EDM machining depend on the alloy, geometry and feature size. EDM holds tolerances to around ±0.002 mm with no cutting force on the part. Exact figures are confirmed against your drawing callouts.